Growing succulents and cacti has become my passion. Unfortunately for the plants in my care, I am still relatively new to the sport so have much to learn with watering being the biggest challenge, until now!
Imagine my despair when I discovered my prize Crested Eve’s Needle (Austrocylindropuntia subulata f. cristata) was covered in a scaly grey fungus!
Not sure how to tackle the problem I started to clean the top part of the plant with a 50/50 milk/water solution to neutralize as I would with white mold. However, as I gently dabbed away at the grey it quickly became apparent this was not the problem. The problem seemed more scaly than fungus.
I then researched scale on succulents – no, as far as I could tell, it was not that either. The internet can be a useful tool but I’ve found advice can vary drastically depending whether advice is from a knowledgeable expert and/or first hand experience or from a content writer who’s never touched a cacti in their life.
I then contacted a FB friend who has been growing cacti most of his life. He arrived early next morning armed with product but once he looked at the poorly plant he admitted he’d never seen anything like it. His suggestion
His suggestion was to carefully remove the scale with a soft brush and treat with disinfectant. As I removed the scaly mold it soon became apparent there was also a problem below soil level.
I researched the internet and the prognosis was not good. Scale? Recommendation: destroy the plant. Was it Botrytis Blight? Not sure.
I then joined a gardening forum and was advised
That is an incredibly bad case of either scale or mealy bugs. Spray the cactus with Insecticidal Soap or rubbing alcohol and then use a soft baby tooth brush to loosen them. Rinse them off with a kitchen sprayer or hose sprayer.
… and use undiluted rubbing alcohol ((isopropyl alcohol) ) not drinking alcohol.
I smashed the terracotta pot to release the plant and to my horor all the scale/mold you can see in the above picture was below the soil line so whatever happened emanated from root level.
After hours of surgery performed with a small artist’s brush and cotton wool pads, I managed to remove all the scale and mold. I then sprayed the plant and soaked the roots with the diluted hydrogen peroxide which acts as a disinfectant.
I repotted in new cactus soil and moved to a shady area to give it time to recover.
Fingers crossed I managed to save the plant.
Ref:
https://sublimesucculents.com/how-to-treat-scale-on-your-succulents-and-cacti/
https://homeguides.sfgate.com/succulent-fungus-28897.html
https://www.gardeningknowhow.com/plant-problems/disease/treating-botrytis-blight.htm
Piglet in Portugal 
Wow… that was hard work! I hope the surgery was successful and the plant lives a long and happy life! 😉
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I love succulents too and have a variety of them in my garden.
I had never come across a crested eve cactus though. Hope you managed to save it, it looks great now Carole.
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I should imagine they do well where you are, Sami. 🙂
I’ve only ever seen it in one garden centre which only specialised in cacti and succulents. Had it been your bog standard cacti I don’t think I’d been so fraught 🙂
Fingers crossed I did not stress it too much when I was trying to save it.
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What?! I can not identify it from the pictures. The ‘skin’ still seems to be intact underneath where the scale was, which is good. Scale and fungus are two completely different pathogens. I can not think of any fungus that would behave like this. Scale seems to be more likely, and is very difficult to eliminate permanently. Did you happen to notice ants swarming the plant? They tend to follow scale, and cultivate them. (That is a long story.) If you can identify the problem as scale, you might want to spray the plant occasionally with horticultural oil. It is a very fine oil that suffocates the scale. If you apply it occasionally, it will prevent scale from getting established. It is sometimes applied to tropical plants for the same reason, and also to improve the sheen of the foliage.
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I think it was the early stages of a type scale. Fortunately i caught it in time and the skin of the plant did not suffer any permanent damage. Another few days would have been a different story. I did not think oil on succulents was recommended as they can’t breath? I don’t know. I’m still new to growing succulents and hve so much to learn.
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That is precisely what I thought about oil on large leaved tropicals, but they somehow tolerate it, and even look better with the sheen of horticultural oil. I though that it was done to barrel cactus that were grown in pots, but I really do not know. It would be worth asking of course, before damaging anything.
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